How far will Miley, Justin, Selena and Taylor Momsen have to go before a parental figure intervenes?

Will they have to have a total meltdown — a la Demi Lovato or Britney Spears – before their parents realize that every kid, and they are still kids, needs a timeout. And I’m not talking about a punishment timeout.I’m talking about a break from a punishing work schedule that would exhaust a mature adult, let alone a teenager with a very skewed upbringing and outlook.

Just take a look at the new photos of Miley Cyrus stumbling into LA’s Chateau Marmont Hotel on March 12 at 1 am. She was barely able to stand up on her own — and why was she out til 3am at 18? How many high-school seniors would be out partying their brains out till 3? Especially if they had just been caught bong-smoking salvia?

Justin Bieber, normally so polite and gracious to his fans and press, finally flipped his lid, and the bird, at a paparazzo on his 17th birthday on March 1, after having dinner with girlfriend Selena Gomez.

Could anyone really blame him for getting stressed out? The kid has been working practically nonstop since being discovered at age 12. Besides touring the world with concerts, he’s performed at the Grammys, the MTV Music Awards, on Saturday Night Live, The Today Show, GMA, appeared on dozens of talk shows, given countless interviews AND then last week he was practically held hostage in his Liverpool hotel as thousands of his fans stormed his hotel.

Who wouldn’t be burned out by this workload? He’s a kid, not a machine.

Then there’s Selena — another good girl who’s usually all smiles in public. The poor thing looked miserable and worn out at LAX airport on the way to NYC to promote her latest single, “Who Says.”

She also, in a highly uncharacteristic move, gave the finger to photographers and fans after having dinner with boyfriend Justin on his B-day.

But then she’s been on a concert tour promoting her album,A Year Without Rain. Selena has also filmed her fourth season of Wizards of Waverly Place and has filmed the movie Monte Carlo with Leighton Meester. And she’s just 18. . . and she’s had death threats from Bieber fans.

Who can blame these kids from cracking?

Miley hosted SNL last week, and over the past year she’s been filming the movies So Undercover and LOL. And she’s been in the middle of her parent’s very public divorce, with her father criticizing her publicly in a GQ magazine article.

Listen, shrinks say it’s really tough to be a child star and Miley’s, Justin’s and Selena’s parents need to be super-protective — not pushing them.

“Parents want their kids to become stars and do what they can to make that happen,” says Beverly Hills psychiatrist Dr. Carole Lieberman. “But the child can no longer be a child and no longer is able to feel as though he/she is loved for herself.”

Being a child star can “lead to a lot of depression and anxiety. It can harm the relationship with the parents who are pushing the child too hard,” warns Dr. Jenn Berman, a marriage, family and child therapist in LA, and author of The A to Z Guide to Raising Happy, Confident Kids.

Got that parental figures?

Stop treating Miley, Justin, and Selena like workhorses and give them some time to relax and just be regular teens.